The present invention relates generally to compressors and more particularly to valve assemblies for use in such compressors.
Various types of reed valves are commonly employed in compressors for controlling the flow of gas to and from the compression chamber. Typically such valve arrangements comprise an elongated relatively thin resilient valve member positioned so as to overlie and selectively close off passageways provided in a valve plate assembly. In typical reciprocating piston type compressors such reed type valve members are commonly mounted in engaging sealing relationship with the valve plate forming one end of the compression chamber and are operated by the pressure differential created by the reciprocating piston.
While such valving arrangements have provided extremely reliable efficient operation over a long period of time, there have arisen applications wherein the noise resulting from the closing slap of the valve member against the valve plate as it moves into a closed position is sufficient to become objectionable.
Accordingly, the present invention provides a means by which this source of potentially objectionable noise may be significantly reduced at relatively low cost and without substantially affecting the overall operating efficiency of the compressor. It has been discovered that by positioning that portion of the valve member which experiences the greatest range of movement in a sightly spaced relationship with respect to the associated valve plate when the valve member is in an at rest condition, significant reduction in the noise level emanating from the compressor is achieved. It appears that this reduction in noise level is due to the substantially lower velocity of the valve member as it moves into the fully closed position. In one embodiment, the valve member is biased into this slightly open position by means of spring generated moments exerted on opposite ends thereof. In another form a resilient member may be employed or alternatively a fixed ramp provided to exert a moment on one or both ends of the reed valve. In yet another embodiment the valve member itself is formed with a slight arcuate bow extending over the length thereof.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.